1. Field of the Invention
The invention relates to toothbrushes.
2. Description of Prior Art
The invention relates more particularly to toothbrushes that emit light and/or sound when in use, and that are therefore particularly useful in monitoring use of the toothbrush and/or aiding in training young persons to brush their teeth correctly.
In U.S. Pat. No. 4,253,212 a toothbrush is disclosed in which a ball or short cylinder is slidable along inside an elongate hollow member, in a handle of a toothbrush, that can be used to provide electric switching. The switching is used to initiate the emission of light or sound due to movement of the handle backwards and forwards, as will take place in normal use during toothbrushing. U.S. Pat. No. 4,253,212 also discloses generating light or sound whenever the toothbrush is flexed, as will normally occur in use when bristles of the toothbrush are urged firmly against a user""s teeth during use. The disclosed switching arrangement is relatively complex and costly.
It is an object of the invention to overcome or at least reduce this problem.
According to the invention there is provided a toothbrush having a hollow handle for housing a battery power supply, one or more light emitting diodes (LED), an integrated electrical circuit and a directionally responsive inertia switching arrangement mounted in the handle, a shank extending from the handle to a brush head with an array of bristles, in which the switching arrangement includes an elongate resilient electrical conductor anchored at one end and constrained to oscillate in a plane parallel to axes of the bristles and acts to open and close an electrical circuit due to brushing movements of the toothbrush to turn the LED""s ON and OFF.
The conductor may be a coiled spring. A plastics channel that may be provided that surrounds the conductor along its length to physically constrain oscillations of the conductor to the plane parallel to the axes of the bristles.
An electrical buzzer may be included in the housing that is initiated by the opening and closing of the circuit.
The toothbrush may include an electrical pressure switch that is arranged to close, whenever the handle is held and the bristles of the brush are firmly urged against surfaces of a user""s teeth, due to relative bending between the handle and the shank.
The integrated circuit is preferably programmed to turn the LED""s ON and OFF in response to the inertial switching arrangement only when the electrical pressure switch is either closed or closed intermittently.